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Zhang X, Lorenceau E, Basset P, Bourouina T, Rouyer F, Goyon J, Coussot P. Wall Slip of Soft-Jammed Systems: A Generic Simple Shear Process. Phys Rev Lett 2017; 119:208004. [PMID: 29219383 DOI: 10.1103/physrevlett.119.208004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Indexed: 06/07/2023]
Abstract
From well-controlled long creep tests, we show that the residual apparent yield stress observed with soft-jammed systems along smooth surfaces is an artifact due to edge effects. By removing these effects, we can determine the stress solely associated with steady-state wall slip below the material yield stress. This stress is found to vary linearly with the slip velocity for a wide range of materials whatever the structure, the interaction types between the elements and with the wall, and the concentration. Thus, wall slip results from the laminar flow of some given free liquid volume remaining between the (rough) jammed structure formed by the elements and the smooth wall. This phenomenon may be described by the simple shear flow in a Newtonian liquid layer of uniform thickness. For various systems, this equivalent thickness varies in a narrow range (35±15 nm).
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Affiliation(s)
- X Zhang
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
| | - E Lorenceau
- Université Grenoble-Alpes, CNRS, LIPhy, 38000 Grenoble, France
| | - P Basset
- Université Paris-Est, ESYCOM EA 2552, ESIEE Paris-CNAM-UPEM, 5 Boulevard Descartes, 77420 Champs sur Marne, France
| | - T Bourouina
- Université Paris-Est, ESYCOM EA 2552, ESIEE Paris-CNAM-UPEM, 5 Boulevard Descartes, 77420 Champs sur Marne, France
| | - F Rouyer
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
| | - J Goyon
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
| | - P Coussot
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 2 Allée Kepler, 77420 Champs sur Marne, France
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Liu PY, Chin LK, Ser W, Chen HF, Hsieh CM, Lee CH, Sung KB, Ayi TC, Yap PH, Liedberg B, Wang K, Bourouina T, Leprince-Wang Y. Cell refractive index for cell biology and disease diagnosis: past, present and future. Lab Chip 2016; 16:634-44. [PMID: 26732872 DOI: 10.1039/c5lc01445j] [Citation(s) in RCA: 210] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cell refractive index is a key biophysical parameter, which has been extensively studied. It is correlated with other cell biophysical properties including mechanical, electrical and optical properties, and not only represents the intracellular mass and concentration of a cell, but also provides important insight for various biological models. Measurement techniques developed earlier only measure the effective refractive index of a cell or a cell suspension, providing only limited information on cell refractive index and hence hindering its in-depth analysis and correlation. Recently, the emergence of microfluidic, photonic and imaging technologies has enabled the manipulation of a single cell and the 3D refractive index of a single cell down to sub-micron resolution, providing powerful tools to study cells based on refractive index. In this review, we provide an overview of cell refractive index models and measurement techniques including microfluidic chip-based techniques for the last 50 years, present the applications and significance of cell refractive index in cell biology, hematology, and pathology, and discuss future research trends in the field, including 3D imaging methods, integration with microfluidics and potential applications in new and breakthrough research areas.
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Affiliation(s)
- P Y Liu
- Université Paris-Est, UPEM, F-77454 Marne-la-Vallée, France.
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Liu PY, Chin LK, Ser W, Ayi TC, Yap PH, Bourouina T, Leprince-Wang Y. An optofluidic imaging system to measure the biophysical signature of single waterborne bacteria. Lab Chip 2014; 14:4237-4243. [PMID: 25205636 DOI: 10.1039/c4lc00783b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this paper, for the first time, an on-chip optofluidic imaging system is innovated to measure the biophysical signatures of single waterborne bacteria, including both their refractive indices and morphologies (size and shape), based on immersion refractometry. The key features of the proposed optofluidic imaging platform include (1) multiple sites for single-bacterium trapping, which enable parallel measurements to achieve higher throughput, and (2) a chaotic micromixer, which enables efficient refractive index variation of the surrounding medium. In the experiments, the distinctive refractive index of Echerichia coli, Shigella flexneri and Vibrio cholera are measured with a high precision of 5 × 10(-3) RIU. The developed optofluidic imaging system has high potential not only for building up a database of biophysical signatures of waterborne bacteria, but also for developing single-bacterium detection in treated water that is in real-time, label-free and low cost.
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Affiliation(s)
- P Y Liu
- Université Paris-Est, UPEM, F-77454 Marne-la-Vallée, France
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Liu P, Chin L, Ser W, Ayi T, Yap P, Bourouina T, Leprince-Wang Y. Real-time Measurement of Single Bacterium's Refractive Index Using Optofluidic Immersion Refractometry. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.proeng.2014.11.743] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zhu WM, Liu AQ, Bourouina T, Tsai DP, Teng JH, Zhang XH, Lo GQ, Kwong DL, Zheludev NI. Microelectromechanical Maltese-cross metamaterial with tunable terahertz anisotropy. Nat Commun 2013; 3:1274. [PMID: 23232404 PMCID: PMC3535344 DOI: 10.1038/ncomms2285] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 11/14/2012] [Indexed: 11/09/2022] Open
Abstract
Dichroic polarizers and waveplates exploiting anisotropic materials have vast applications in displays and numerous optical components, such as filters, beamsplitters and isolators. Artificial anisotropic media were recently suggested for the realization of negative refraction, cloaking, hyperlenses, and controlling luminescence. However, extending these applications into the terahertz domain is hampered by a lack of natural anisotropic media, while artificial metamaterials offer a strong engineered anisotropic response. Here we demonstrate a terahertz metamaterial with anisotropy tunable from positive to negative values. It is based on the Maltese-cross pattern, where anisotropy is induced by breaking the four-fold symmetry of the cross by displacing one of its beams. The symmetry breaking permits the excitation of a Fano mode active for one of the polarization eigenstates controlled by actuators using microelectromechanical systems. The metamaterial offers new opportunities for the development of terahertz variable waveplates, tunable filters and polarimetry.
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Affiliation(s)
- W M Zhu
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
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Yu YF, Ren M, Zhang JB, Bourouina T, Tan CS, Tsai JM, Liu AQ. Force-induced optical nonlinearity and Kerr-like coefficient in opto-mechanical ring resonators. Opt Express 2012; 20:18005-18015. [PMID: 23038348 DOI: 10.1364/oe.20.018005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This paper demonstrates the optical nonlinearity in opto-mechanical ring resonators that consist of a bus waveguide and two ring resonators, which is induced by the optical gradient force and characterized by the Kerr-like coefficient. Each ring resonator has a free-hanging arc that is perpendicularly deformable by an optical gradient force and subsequently this deformation changes the effective refractive index (ERI) of the ring resonator. The change of the ERI induces optical nonlinearity into the system, which is described by an equivalent Kerr coefficient (Kerr-like coefficient). Based on the experimental results, the Kerr-like coefficient of the ring resonator system falls in the range from 7.64 × 10(-12) to 2.01 × 10(-10) m(2)W(-1), which is at least 6-order higher than the silicon's Kerr coefficient. The dramatically improved optical nonlinearity in the opto-mechanical ring resonators promises potential applications in low power optical signal processing, modulation and bio-sensing.
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Affiliation(s)
- Y F Yu
- School of Electrical & Electronic Engineering, Nanyang Technological University, 639798 Singapore
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Yu YF, Fu YH, Zhang XM, Liu AQ, Bourouina T, Mei T, Shen ZX, Tsai DP. Pure angular momentum generator using a ring resonator. Opt Express 2010; 18:21651-21662. [PMID: 20941064 DOI: 10.1364/oe.18.021651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper reports a pure angular momentum generator using a ring resonator surrounded by a group of nano-rods. The evanescent waves of the circulating light in the ring are scattered by the nano-rods and generate a rotating electromagnetic field, which has only angular momentum but no linear momentum along the axis of rotation. The angular order is determined by the difference between the order of Whispering Gallery mode and the number of the rods, the rotating frequency is equal to the light frequency divided by the angular order. The maximum amplitude of the rotating electromagnetic fields can be 10 times higher than the amplitude of the input field when there are 36 rods (R(rod) = 120 nm, nr = 1.6). The pure angular momentum generator provides a new platform for trapping and rotation of small particles.
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Affiliation(s)
- Y F Yu
- School of Electrical & Electronic Engineering, Nanyang Technological University, 639798 Singapore
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Cai H, Liu B, Zhang XM, Liu AQ, Tamil J, Bourouina T, Zhang QX. A micromachined tunable coupled-cavity laser for wide tuning range and high spectral purity. Opt Express 2008; 16:16670-16679. [PMID: 18852775 DOI: 10.1364/oe.16.016670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This paper presents the design and experimental study of a coupled-cavity laser based on the micromachining technology for wide tuning range and improved spectral purity. The core part of this design utilizes a deep-etched movable parabolic mirror to couple two identical Fabry-Pérot chips and thus allows the active adjustment of the cavity gap so as to optimize the mode selection and to increase the tuning range as well. In experiment, the laser achieves the single longitudinal mode output over 51.3 nm and an average side-mode-suppression ratio of 22 dB when the tuning current varies from 5.7-10.8 mA. The measured wavelength tuning speed is 1.2 micros and the single mode output is stable at any wavelength when the tuning current is varied within +/- 0.06 mA. Compared with the conventional fixed cavity gap coupled-cavity lasers, such design overcomes the phase mismatching and mode instability problems while maintaining the merit of high-speed wavelength tuning using electrical current.
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Affiliation(s)
- H Cai
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
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